where \(Q:=\frac{1}{6}\Delta R+\frac{1}{16}\star \mbox{Pf} \)    is Tom Branson's celebrated Q-curvature [1]}The actual expression for \(Q\)  is \(\frac{1}{6}\Delta R+ \frac{1}{16}\star \mbox{Pf}-\frac{1}{4}|W|^{2}\)  where \(W\)  is the Weyl curvature, \(R\)  is the scalar curvature and Pf is the Pfaffian 4-form. It is known that \(W\)  vanishes for a conformally flat manifold..
Clearly, the left hand side of (REF ) is a divergence. Therefore, the quantity \(\frac{1}{16}\star \mbox{Pf}\)  must also be a divergence.
It is expected that a link should exist between a good Coulomb frame and the energy (REF ) .
